Impact of tear osmolarity in the biometric pre-assessment for phacoemulsification surgery

Abstract

Purpose : To compare the biometric measurements, the best-corrected and uncorrected visual acuity, manifested refractive spherical equivalent (MRSE), tear film osmolarity value, and the ocular surface disease index (OSDI) score in patients with preoperative normal and abnormal tear osmolarity

Methods : This is a prospective, observational, comparative study conducted at the Asociación para Evitar la Ceguera en México I.A.P., Mexico. We included a total of 60 patients undergoing phacoemulsification cataract surgery. In Group 1, we included 30 cataract patients with a preoperative tear osmolarity value < 308 mOsm/L in both eyes and inter eye difference < 8 mOsm/L, whereas in Group 2, we included 30 cataract patients with tear osmolarity values > 312 mOsm/L. A paired t-test was used to assess statistical significance between groups in normally distributed data; whereas the Mann-Whitney test was employed in non-normal distributed data. In addition, the Pearson’s correlation coefficient (r) was obtained for all measurements, and linear regression analysis (R2) were performed. Normal and non-normal distributions were determined by Shapiro-Wilk tests for all variables. Statistical analyses were performed using the Statistical Package for Social Sciences (SPSS) software (version 20, SPSS, Inc., Chicago, IL; USA). Graphs and layouts depicted in Figures were elaborated using the 2015 GraphPad software Inc. Prism version 6.0.

Results : Tear osmolarity of 135 right eyes from patients between 39 to 87 years (mean 65 +-SD 11.17) was analyzed. 49 were male and 86 female. Osmolarity values obtained were 303.5 +_ 9.227 mOsm/L; range from 278 mOsm/L and 327 mOsm/L. Mean keratometry values were 44.49 D +- 1.72 (range 41.88 - 48.5 D). Keratometry measurements comparing different osmolarity values between both groups <308 mOsm/L and >308 mOsm/L were not significant (p=0.742). Although not significant, there is a tendency towards a decrease in keratometry values with lower osmolarity values. Final results will be analyzed once data is complete. (December 2018)

Conclusions : Previous studies have reported a change in keratometries with different osmolarity values. We found a tendency towards a decrease in keratometries with lower osmolarity, which might become statistically significant when we reach the stablished sample size.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.